Polarization-Graded AlGaN Solar-Blind p-i-n Detector With 92% Zero-Bias External Quantum Efficiency

Kalra, Anisha and Rathkanthiwar, Shashwat and Muralidharan, Rangarajan and Raghavan, Srinivasan and Nath, Digbijoy N (2019) Polarization-Graded AlGaN Solar-Blind p-i-n Detector With 92% Zero-Bias External Quantum Efficiency. In: IEEE PHOTONICS TECHNOLOGY LETTERS, 31 (15). pp. 1237-1240.

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Abstract

We report on record high zero-bias external quantum efficiency (EQE) of 92% for back-illuminated Al0.40Ga0.60N p-i-n ultra-violet (UV) photodetectors on sapphire. The zero-bias responsivity measured 211 mA/W at 289 nm, which is the highest value reported for solar-blind, p-i-n detectors realized over any epitaxial wide band-gap semiconductor. This is also the first report for a p-i-n detector, where a polarization-graded Mg-doped AlGaN layer is utilized as the p-contact layer. The devices exhibited a ten-orders of magnitude rectification, a low reverse leakage current density of 1 nA/cm(2) at 10 V, a high R(0)A product of 1.3 x 1011 Omega.cm(2) and supported fields exceeding 5 MV/cm. The light-to-dark current ratio and the UV-to-visible rejection ratio for the detectors exceeded six-orders of magnitude and the thermal noise limited detectivity (D*) measured 6.1 x 1014 cmHz(1/2)W(-1). The state-of-the-art performance parameters can be attributed to a high crystalline quality absorbing AlGaN epi-layer resulting from the use of an AlN/AlGaN superlattice buffer and an improved p-contact via polarization grading.

Item Type:	Journal Article
Publication:	IEEE PHOTONICS TECHNOLOGY LETTERS
Publisher:	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Additional Information:	copyright for this article belongs to IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Keywords:	Aluminium gallium nitride (AlGaN); epitaxial growth; p-i-n photodiodes; metal organic chemical vapor deposition (MOCVD); solar-blind; ultra-violet detectors
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	03 Sep 2019 10:24
Last Modified:	03 Sep 2019 10:24
URI:	http://eprints.iisc.ac.in/id/eprint/63400

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